The present invention relates to the field of computer software measurement tools. In particular, the present invention discloses a method and apparatus for determining the performance of a client-server based application.
Since the 1980""s there has been a paradigm shift in the enterprise computer system industry away from enterprise programs running on mainframes that are accessed by xe2x80x9cdumbxe2x80x9d terminals towards client-server enterprise systems. Furthermore, there has been a shift from local access to remote access using a computer network. A client-server enterprise system has an intelligent client application that is used by an end user and a server computer system that stores large amount of information. The client application consults the server computer system across a computer network when the client application needs information or services provided by the server. The computer network may be a local area network, a private wide area network, a virtual private network built using encryption tunnels on a public network, or a public network such as the global Internet. A single computer server may be used to serve multiple client applications running on multiple different client systems.
To determine how well an enterprise application is performing, performance monitoring hardware and/or software is used. The task of monitoring performance of a mainframe/terminal computer application is relatively simple. Monitoring the performance of a mainframe/terminal computer application is simple because the user""s terminal is a direct local connection between the terminal and the mainframe. Therefore, no significant performance variations are introduced by the direct local connection. Furthermore, the user""s xe2x80x9cdumbxe2x80x9d terminal will usually behave in a deterministic manner such that no significant performance variations are introduced by the dumb terminal. Thus, to monitor the performance of a mainframe/terminal computer application an information systems person only needs to monitor the performance of the mainframe computer.
The task of monitoring the performance of a client-server application is not nearly as simple. In a client-server system there are many potential bottlenecks. For example, the client application may be misconfigured, the client computer may be underpowered, the computer network link may be saturated, a router or bridge on the network may be inoperative, the server system may be overloaded, or a database accessed by the server application may be slow. Thus, the task of monitoring a distributed client-server application is quite difficult. It would be desirable to have a client-server performance monitoring system that is simple to install, simple to operate, and provides a detailed description of where in the client-server system a performance problem is originating.
A client-server software performance monitor system is disclosed. In the system of the present invention, a performance monitor machine is coupled to a computer network in close network proximity to one or more server systems that are to be monitored. The performance monitor machine monitors all network communication originating from or addressed to the server system. The performance monitor machine determines client-server transaction times using the times of network packets that are detected.
The performance monitor machine detects client requests sent to the server system to determine a time when the server system receives a request packet from a client system. The performance monitor machine then detects one or more response packets addressed to the client system that sent the request. Each response packet is time-stamped to record the time or times when the server system sent each response packet to the client system. Finally, the performance monitor machine detects one or more acknowledgement packets from the client system that acknowledge receipt of the server response packets.
The performance monitor machine calculates a server processing time by subtracting the time when the server system receives the request packet from a client system from the time when the server system sends the first response packet back to the client system. The performance monitor machine also calculates an network transit time by subtracting said time when the server system receives a final acknowledgement packet from the time when said server system sent the first response packet to the client system. The performance monitor machine calculates an approximate total client observed response time by adding the server processing time and the approximate network transit time.